• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.5 no.1
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• pp.55-78
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• 2001

Given the anisotropic Poisson equation $-{\nabla}{\cdot}{\mathcal{K}}{\nabla}p=f$, one can convert it into a system of two first order PDEs: the Darcy law for the flux $u=-{\mathcal{K}{\nabla}p$ and conservation of mass ${\nabla}{\cdot}u=f$. A very natural mixed finite volume method for this system is to seek the pressure in the nonconforming P1 space and the Darcy velocity in the lowest order Raviart-Thomas space. The equations for these variables are obtained by integrating the two first order systems over the triangular volumes. In this paper we show that such a method is really a standard finite element method with local recovery of the flux in disguise. As a consequence, we compare two approaches in analyzing finite volume methods (FVM) and shed light on the proper way of analyzing non co-volume type of FVM. Numerical results for Dirichlet and Neumann problems are included.

• Journal of KIISE:Software and Applications
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• v.30 no.3_4
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• pp.285-292
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• 2003

Existing MPEG-4 players have limitation of screen blinks and drops of object rendering speed when user insert, delete, and replace objects on scenes. In this paper, an Object Priority Order Composition operated through the MPEG-4 player is proposed. This composition is the method for presentation user can insert, delete, and replace scene objects more efficiently. Therefore, this composition can show the MPEG-4 multimedia scenes without blinks and delays on MPR-4 player may seem random and natural.

• Journal of the Korean Mathematical Society
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• v.51 no.5
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• pp.1045-1073
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• 2014

The study of the identities of symmetry for the Bernoulli polynomials arises from the study of Gauss's multiplication formula for the gamma function. There are many works in this direction. In the sense of p-adic analysis, the q-Bernoulli polynomials are natural extensions of the Bernoulli and Apostol-Bernoulli polynomials (see the introduction of this paper). By using the N-fold iterated Volkenborn integral, we derive serval identities of symmetry related to the q-extension power sums and the higher order q-Bernoulli polynomials. Many previous results are special cases of the results presented in this paper, including Tuenter's classical results on the symmetry relation between the power sum polynomials and the Bernoulli numbers in [A symmetry of power sum polynomials and Bernoulli numbers, Amer. Math. Monthly 108 (2001), no. 3, 258-261] and D. S. Kim's eight basic identities of symmetry in three variables related to the q-analogue power sums and the q-Bernoulli polynomials in [Identities of symmetry for q-Bernoulli polynomials, Comput. Math. Appl. 60 (2010), no. 8, 2350-2359].

• Bulletin of the Korean Mathematical Society
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• v.54 no.4
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• pp.1373-1386
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• 2017

In this paper, we introduce and explore suggested notions of 'above', 'below' and 'between' in general groupoids, Bin(X), as well as in more detail in several well-known classes of groupoids, including groups, semigroups, selective groupoids (digraphs), d/BCK-algebras, linear groupoids over fields and special cases, in order to illustrate the usefulness of these ideas. Additionally, for groupoid-classes (e.g., BCK-algebras) where these notions have already been accepted in a standard form, we look at connections between the several definitions which result from our introduction of these ideas as presented in this paper.

• Journal of the Korean housing association
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• v.10 no.4
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• pp.161-174
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• 1999

This study tried to search for solutions of present problems in architecture through interdisciplinary study which includes biology, literature, aesthetics, and psychology, and set up two models composed of the nature and the human perception which contemporary architecture has problems on. By nature-oriented approach through biology and romanticist literature, the five types of organic principles which could be obtained from structure and order in natural system and by human perception-oriented approach through aesthetic theory of Harold Osborne and perceptual and cognitive psychology the structure and order of perceptual arousal, perceptual balance, and perceptual order in human cognition based on perceptual appropriateness could be found. The unified and organic framework of architectural composition must be considered through a deductive and inductive study as this study was approached. The results of the present study can be applied to construct human-oriented design principles and factors in architectural space and form, and better environmental quality.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.876-880
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• 2000

Vibration problem of deckhouse structure in a container vessel was investigated through the analysis and measurement. The natural frequency of deckhouse structure was found to be resonant with main engine 4th order excitations in the operating range, major sources of which were main engine inertial moment and axial thrust of the propulsion shafting system. To investigate and solve the problem, exciter test was performed to identify the vibration chracteristics of the ship structure and mechanical balancer was installed to compensate the 4th order inertial moment. Measurement results under the conditions with and without balancer operating were compared and analyzed to confirm the balancer effect. Good coincidence was found between the measurement and analysis results, which made it possible to predict the vibration problem in the earlier design stage.

• Steel and Composite Structures
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• v.37 no.1
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• pp.37-49
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• 2020

In this paper, free vibration finite element analysis of axially moving laminated composite beams subjected to axial tension is studied. It is assumed that the beam has a constant axial velocity and is subject to uniform axial tension. The analysis is based on higher-order theories that have been presented by Carrera Unified Formulation (CUF). In the CUF technique, the three dimensional (3D) displacement fields are expressed as the approximation of the arbitrary order of the displacement unknowns over the cross-section. This higher-order expansion is considered in equivalent single layer (ESL) model. The governing equations of motion are obtained via Hamilton's principle. Finally, several numerical examples are presented and the effect of the ply-angle, travelling speed and axial tension on the natural frequencies and beam stability are demonstrated.

• Journal of KSNVE
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• v.9 no.5
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• pp.914-921
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• 1999

There are many theoretical investigations to analyze higher order mode of reactive type single expansion chambers with offset inlet/outlet locations. But the conventional method has the restriction that the ratio between the area of inlet(or outlet) pipe and that of chamber must be natural number. In the paper, a new method was suggested to apply the Kim's method to silencer with circular cross-section. Not only the offset location but also the magnitude of cross-section area of inlet/outlet pipe can be considered by the suggested method. The predictions by this new method also compared with those by the finite element method and Munjal's method in order to verify the accuracy of the suggested method presented here.

• Animal Systematics, Evolution and Diversity
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• v.23 no.2
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• pp.175-181
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• 2007

Some hydromedusae were collected from Gijang (Busan), Yeounggwang, Munseom (Jejudo Is.) and Shinhangman with Issacc-Kidd Midwater trawl net or by SCUBA diving from 2001 to 2003. They were identified into five species of five families in three orders and are new to the Korean fauna. Bougainvillia ramosa (van Benenden, 1844) of the family Bougainvilliidae in the order Anthomedusae, Phialidium hemishaericum (Linne, 1767) of the family Campanulariidae and Aeguorea macrodactyla of the family Aequoreidae in the order Leptomedusae, Diphyes dispar (Chamisso and Eysenhardt, 1821) of the family Diphydae and Abylopsis tetragona (Otto, 1823) of the family Abylidae in the order Siphonophora. With a result of this work, the Korean hydromedusa fauna consists of 31 species of 18 families in six orders.

• Structural Engineering and Mechanics
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• v.31 no.5
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• pp.587-603
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• 2009

We performed a free vibration analysis of skew composite laminates with or without cutout based on the high-order shear deformation plate theory (HSDT). The effects of skew angles and ply orientations on the natural frequencies for various boundary conditions are studied using a nonlinear high-order finite element program developed for this study. The numerical results are in good agreement with those reported by other investigators for simple test cases, and the new results reported in this paper show the interactions between the skew angle, layup sequence and cutout size on the free vibration of the laminate. The findings highlight the importance of skew angles when analyzing laminated composite skew plates with cutout or without cutout.